The principal aim of this study is to evaluate the effects of China's one-child policy on the physical, academic, and personality characteristics of its children. The project will make important contributions to scientific knowledge about the health-related implications of family size. This study will allow us to compare the results from the Western literature to those from a non-Western country seeking to upgrade its economic development. Even in the West, a study of the scale proposed for this project, examining the relative impact of socioeconomic and personal relationship factors on children's physical, academic, and personality outcomes, does not exist. Thus, the proposed study's will allow us to test Western theories about the underlying causes of family size effects on the outcomes of Chinese children. The results of the proposed study will provide invaluable information for scientists and health practitioners attempting to understand the relationship between family planning policies and children's well-being. The proposed study will obtain data from about 4000 schoolchildren in Beijing Municipality, and in the three provinces of Anhui, Gansu, and Hunan. Data on the physical characteristics of height and weight will be gathered directly; data on academic characteristics will be based on the performance of the students on standardized achievement tests ,and on their current school-based test scores in math and the Chinese lanquage. Data on the personality characteristics of the children will be collected from mothers,